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Slide Rules

Index by Makers & Retailers

Hundreds of companies around the world were involved in the production of slide rules from the 18th to the 20th centuries. Click on one of the names below to see the objects in this collection that were associated with that firm.

In 1950 and 1951, three Illinois Institute of Technology engineering professors participated in the development of the Versalog slide rule, manufactured by Hemmi of Tokyo, Japan, for the Frederick Post Company of Chicago. E. I. Fiesenheiser, R. A. Budenholzer, and B. A. Fischer subsequently prepared this 115-page hardcover volume explaining the slide rule's capabilities. They covered the care of the instrument, its twenty-three scales, multiplication and division, squares and cubes, exponentials and logarithms, and trigonometric operations. Each professor also contributed a chapter on applications in his specialty: civil, mechanical, or electrical engineering.

This copy is stamped inside the front cover and on the edges: WILLIAM KRUTZ ESQ. See 1978.0800.01.

Pickett, Inc., was a slide rule manufacturer that started in Chicago in 1943, shifted most of its operations to Alhambra, Calif., in 1946, and moved to Santa Barbara, Calif., in 1964. Maurice L. Hartung, a mathematics professor at the University of Chicago, wrote several instruction manuals for the company, including How to Use Dual Base Log Log Slide Rules. This 93-page booklet was intended for use with Pickett models 2, 3, and 4. It contains sections on the general operation of a slide rule, the use of scales for trigonometry and roots, elementary vector methods, the use of logarithmic scales, practice problems, hyperbolic functions, and circular functions. Hartung also showed how the double T scales could solve side-angle-side triangle problems in one step. Model 600 was advertised at the back of the manual, and instructions for caring for Pickett slide rules were provided inside the back cover.

Although Hartung wrote the manual in 1947, this printing was made after the company moved to Santa Barbara in 1964. See the associated items, 1980.0097.01 and 1980.0097.06.

This eight-page pamphlet, titled How to Use Model 3 Powerlog Slide Rules, is a supplement to Maurice L. Hartung, How to Use Dual Base Log Log Slide Rules (Santa Barbara, Calif.: Pickett, Inc., 1947). Hartung also wrote this pamphlet, probably around 1947. He explains scales not found on other Pickett models, namely, the extended square root, cube root, and tangent scales. Model 3 also had an extra log log scale (LL0).

This printing was made after the company moved to Santa Barbara in 1964. See the associated items, 1980.0097.01 and 1980.0097.05.

The cover of this eight-page pamphlet is blue and black. It reads: HOW THE (/) OTIS KING (/) SPIRAL (/) SLIDE RULE (/) SAVES TIME (/) AND MISTAKES (/) IN ALL (/) CALCULATIONS (/) SIMPLE (/) QUICK (/) ACCURATE. The text describes the features and advantages of the Otis King cylindrical slide rule. Drawings demonstrate the three steps required to make calculations with the instrument. The pamphlet also lists 13 sample problems the Otis King Pocket Calculator could solve, 37 companies that were major customers of the rule, and 50 professions that usefully employed the rule. The back page carries five anonymous testimonials.

This pamphlet arrived with 1981.0922.09 and 1981.0922.11. It is exactly the same as 1989.3049.04, except that it is not stamped with information about where the rule was purchased.

This 16-page pamphlet was printed on light green paper by Carbic Limited, the London manufacturer of the cylindrical slide rule invented by Otis King. It is titled: The Otis King Calculator: Instructions for Use. This form of pamphlet is typically found with King Calculators manufactured later than those that sold with Carbic's eight-page pamphlet. (See 1987.0788.06.) Thus, it was printed no earlier than the late 1960s. This pamphlet did, though, appear before the pound sterling was decimalized in 1971.

An introduction to the instrument has been added, and explanations have been expanded for multiplication and division, logarithms, and understanding the scales. The further examples are nearly identical to those in the earlier form of instructions. The explanations of how to use the logarithmic capabilities of Model L are the same except that the word "unity" has been replaced by the number 1. Discussions of compound roots and approximation have been added, and the explanation of finding the decimal point is expanded.

This pamphlet folds out to eight pages and was printed on light green paper by Carbic Limited, the British manufacturer of Otis King's Pocket Calculator, a cylindrical slide rule. Carbic's address on the pamphlet—171, Seymour Place, London, W.I.—is scratched out and reprinted as 54, Dundonald Road, London, S.W.19. Dundonald Road was the last known location for Carbic, and the company was there by 1959. The calculator was available by mail order in 1960 for 62s. 6d. (roughly $175.00).

The pamphlet provides details of the scales on the Model K (which performed multiplication and division) and the Model L (which also provided readings of logarithms for determining roots and powers). The examples also include problems of proportion, percentages, constant factors, and calculations in pounds sterling (before decimalization of British currency). The last three pages provide instructions for operating the instrument.

This flyer, printed in blue ink on white paper, is titled: Simplify any Calculation with an Otis King. The text identifies potential users and describes the functions of this cylindrical slide rule. The back of the flyer lists six sample problems the Otis King Pocket Calculator could solve. It is stamped with the address of an English dealer of scientific instruments: H. T. POCKETT. (/) 25. NELSON ROAD. (/) GREENWICH. S.E.10. The price is listed as 47s. 6d. postpaid.

The flyer arrived with 1987.0788.01 and probably dates to the same period, from about 1960 to 1962. See also 1987.0788.06.

The cover of this eight-page pamphlet is blue and black. It reads: HOW THE (/) OTIS KING (/) SPIRAL (/) SLIDE RULE (/) SAVES TIME (/) AND MISTAKES (/) IN ALL (/) CALCULATIONS (/) SIMPLE (/) QUICK (/) ACCURATE. The text describes the features and advantages of the Otis King cylindrical slide rule. Drawings demonstrate the three steps required to make calculations. The pamphlet also lists 13 sample problems the Otis King Pocket Calculator could solve, 37 companies that were major customers of the rule, and 50 professions that usefully employed the rule. The back page carries five anonymous testimonials and is stamped in blue ink with the address of the instrument's U.S. distributor: CALCULATOR COMPANY (/) BOX 593 (/) LAKEWOOD, CALIFORNIA 90714.

In this instrument a white rectangular plastic sheet slides between two white discs that are held together with black plastic bars and metal grommets. The sheet is marked in green on both sides, with a polar grid and rectangular grid on one side and a polar grid on the other side. The front disc has scales for altitude computations at the top and for air speed computations at the bottom. The back disc has a scale to correct direction readings for wind and a scale for converting temperature readings from degrees Centigrade to Fahrenheit. The center of the back disc is clear for viewing the grid. A salmon plastic sheath stores the instrument.

The device is marked on the front: DALTON DEAD RECKONING COMPUTER (/) TYPE E-6B. It also is marked: WEEMS SYSTEM OF NAVIGATION (/) (A DIVISION OF JEPPESEN & CO.) (/) DENVER, COLORADO; PAT. NO. 2,097,118. The grid is marked in pencil: FL[IGH]T OFF COURSE (/) 2 MILES/SQUARE. The back of the disc is also marked in pencil. The three lines in the clear part of the disc are illegible, but below the temperature conversion scale, the marks read: 3.5° F/1000'. A ring at the top of one black plastic bar is marked: U.S. PAT. 3,112,875.

Naval Reserve pilot Philip Dalton, in consultation with navigation instructor Philip Van Horn Weems, developed the Dalton dead reckoning computer for the U.S. Army Air Corps and received a patent in 1937. The device was widely used during World War II.

After the war, many manufacturers in the United States and Europe made the E-6B. Elrey Borge Jeppesen, a pilot for what became United Airlines, founded his company in 1934 and moved it to Denver in 1941. Jeppesen & Co. made aeronautical charts and navigational tools and guides. It became a subsidiary of Boeing in 2000. The patent number on the back of this object refers to the design of the computer with the gridded rectangular sheet and two discs. The patentees were employed by Felsenthal Instruments Co., which frequently supplied companies with the plastic for manufacturing Dalton computers in the 1950s and 1960s.

The donor purchased this object around 1965 and used it for about two years in airplane navigation.

Relatively late in its history of making and selling slide rules, the Eugene Dietzgen Co. of Chicago began developing products that competed with the high-end slide rule lines manufactured by Keuffel & Esser (namely, model 4081) and Post (the Versalog). This two-sided, ten-inch wooden slide rule is coated with white plastic and has metal endpieces. On one side the base has LL02, LL03, DF, D, LL3, and LL2 scales, with CF, CIF, L, CI, and C scales on the slide. The top of the base is marked: DIETZGEN MICROGLIDE TM DECIMAL TRIG TYPE LOG LOG CAT. NO. 1734.

On the other side, the base has LL01, K, A, D, DI, and LL1 scales, with B, T < 45°, T > 45°, ST, and S scales on the slide. The top of the base is marked: EUGENE DIETZGEN CO. PATS. 2,170,144 2,285,722 PAT'S PEND. MADE IN U.S.A. 020038. On both sides the right end of the rule has formulas indicating the functions represented by the scales. The glass indicator has a metal and black plastic frame; both edges are marked: DIETZGEN.

The rule fits in a black leather case with a metal clasp. A Dietzgen logo is on the flap—the letter D inside the letter E inside the letters Co. In 1959 Dietzgen introduced the Microglide line of slide rules, which featured Teflon-lined grooves on the base so that the slide moved more smoothly. According to Ian Lodge's estimated production figures, the serial number suggests a manufacture date for this object of 1962.

Dietzgen ceased the production of slide rules around 1972. The arrangement of scales corresponds to those depicted in a 1960 instruction manual for the "Dietzgen Decimal Trig Type Log Log Slide Rule," although the "Microglide" trademark is not mentioned. See 1986.0790.01 for information on the patents mentioned on the instrument. The indicator is Dietzgen's "framed full vision" type and is covered by U.S. Patent 2,634,912, issued to Clarence P. Davey on April 14, 1953.

The donor, Ed Severino, began his career as an engineer with General Electric Company in Schenectady, N.Y. After eight years, he left to teach mathematics and science at Mont [sic] Pleasant High School in Schenectady, where he became head of the Technical Department. The slide rule is of the type trainees used in the late 1970s and early 1980s, when Severino was director of his high school's General Electric Apprentice Training Educational Program.